the dss i am talking about is #5 in dh's family with his first wife. he's 12 and dh feels like he is in a battle to win him over so he ignores behavior in him that he would never tolerate in any of the other kids (even his). #1 and #3 live with us full time and are wonderful young men, #2 got kicked out of the house for drugs and now lives with mom. #4 and #5 are supposed to be 50- 50 , but #4 is the only girl and has chosen to stay with her mom. the courts and the police have done nothing to enforce the 50-50 order. dh loves his kids and really wants to protect them from the toxic envirnment at their moms'. he feels the best way to do this is to get dss to choose to live with him. to faccilitate this choice he is doing everything to make life easy and pleasant for dss. he is very passionate about "saving" this kid from the horrible fate that he thinks lies in store for him if he stays with his mom. i can see that his moms house is full of yelling and very superficial, looks and brand names, image means everything. i knew this whole situation up front, i was told by dh that if i had a problem with it, or ever made life difficult for dss our relationship would not work. i knew going into it, but i was ok with it then, for one reason due to the fact that dss was sooo well behaved.
lately he has gotten cheeky and very into image, and i'm venting here since i can't to dh. here are some examples of things that have been said that NO ONE else in the house would get away with.
i'm working on ds age 6 talking lower in public. while waiting for the table i tell him that i'll give him thums up or down while he's talking to remind him. dss says "thats silly- its like school or something" i say "well i used to be a teacher" dss says "but we're not at school people will look at us funny", i say "we may not be at school, but i am teaching" and then dropped it.
later that night i put the baby in a back wrap for the first time and asked dh how i looked. he didn't hear me but dss did and said "ugly" he later asked if we had to carry the baby that way- the insinuation was that he was embarassed.
i understand why dh lets dss get away with this- in his mind a little snottiness is better than a life of drugs and yelling. and dss is not that bad of a kid- but my feelings are starting to be hurt. i genuinly care about dss- i do alot for him- does he realize how mean he is being? i can't tell him- dh would flip. dh says if it continues he'll talk to him, but it's always little things that add up- so i haven't told him. am i being too sensitive? i really want dss to grow up to a healthy adult and caring so much for appearances and belittling people is not healthy!
ok vent done- it does help to get it off my chest!

You have every right to call you dss on his rude behaviour. By allowing his son to disrespect you, your husband is disrespecting you.

That being said, there are ways to call him on it that will not cause a riot. The next time he is rude, simply look him in the eye and say "That was hurtful and rude. I do not treat you in that manner and I expect you to treat me with the same respect." Then leave it at that. Don't overreact, don't yell, maintain your calm.

Also, talk to his older siblings, perhaps they have noticed the behaviour and would be willing to talk to him about it.

DSS is acting out because of the mixed message his father is sending him. Kids need limits on their behaviour. Your husband should stop trying to make life seem easier at Dad's house and TALK TO HIS CHILDREN ABOUT THE SITUATION AT MOTHER'S HOUSE. Stress the importance of opening the lines of communication over just giving the child an easy ride.

Finally, you need to talk to your husband about how his permissive attitude is affecting your relationship with him and his child. Explain that you would not allow the children to disrespect him, and therefore he should not allow it to happen to you. He can call it a phase, however he is setting a precedent for how his son will go through life, in other words he is setting him up for failure. Oh, and your husband is aware of how dss treats you, he just closes it up because he doesn't know how to deal.

Kudos to you on your reaction to the dinner table comments, well done!

Good luck! I know how hard a blended family can be, I came from one and I am a stepmother as well. My dss had difficulty accepting me in the maternal role, but we overcame it and we have a wonderful relationship.